/*
 ============================================================================
 Name        : base_io.c
 Author      : Qiniu.com
 Copyright   : 2012(c) Shanghai Qiniu Information Technologies Co., Ltd.
 Description :
 ============================================================================
 */

#include "base.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>

#if defined(__APPLE__)
#include <TargetConditionals.h>
#endif

#ifdef _WIN32
#include "emu_posix.h" // for type Qiniu_Posix_File
#else
#include <unistd.h>
#define Qiniu_Posix_Handle int
#define Qiniu_Posix_Open open
#define Qiniu_Posix_Pread pread
#define Qiniu_Posix_Fstat fstat
#define Qiniu_Posix_Close close
#define Qiniu_Posix_InvalidHandle -1
#endif

#ifndef O_BINARY
#define O_BINARY 0
#endif

/*============================================================================*/
/* type Qiniu_Crc32 */

static const unsigned long crcTable[256] =
	{
		0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535,
		0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD,
		0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D,
		0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
		0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
		0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
		0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC,
		0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
		0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB,
		0xB6662D3D, 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
		0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB,
		0x086D3D2D, 0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
		0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA,
		0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE,
		0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
		0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
		0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409,
		0xCE61E49F, 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81,
		0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739,
		0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
		0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268,
		0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0,
		0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8,
		0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
		0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
		0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703,
		0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7,
		0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
		0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE,
		0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
		0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6,
		0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
		0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D,
		0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5,
		0x47B2CF7F, 0x30B5FFE9, 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
		0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
		0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D};

unsigned long Qiniu_Crc32_Update(unsigned long inCrc32, const void *buf, size_t bufLen)
{
	unsigned long crc32;
	unsigned char *byteBuf;
	size_t i;

	/** accumulate crc32 for buffer **/
	crc32 = inCrc32 ^ 0xFFFFFFFF;
	byteBuf = (unsigned char *)buf;
	for (i = 0; i < bufLen; i++)
	{
		crc32 = (crc32 >> 8) ^ crcTable[(crc32 ^ byteBuf[i]) & 0xFF];
	}
	return crc32 ^ 0xFFFFFFFF;
}

static size_t Qiniu_Crc32_Fwrite(const void *buf, size_t cbelem, size_t n, Qiniu_Crc32 *self)
{
	self->val = Qiniu_Crc32_Update(self->val, buf, n);
	return n;
}

Qiniu_Writer Qiniu_Crc32Writer(Qiniu_Crc32 *self, unsigned long inCrc32)
{
	Qiniu_Writer writer = {self, (Qiniu_FnWrite)Qiniu_Crc32_Fwrite};
	self->val = inCrc32;
	return writer;
}

/*============================================================================*/
/* Qiniu_BufReader */

static size_t Qiniu_ReadBuf_Read(void *buf, size_t unused, size_t n, Qiniu_ReadBuf *self)
{
	Qiniu_Int64 max = self->limit - self->off;
	if (max <= 0)
	{
		return 0;
	}
	if ((Qiniu_Int64)n > max)
	{
		n = max & (~(size_t)0L);
	}
	memcpy(buf, self->buf + self->off, n);
	self->off += n;
	return n;
}

static ssize_t Qiniu_ReadBuf_ReadAt(Qiniu_ReadBuf *self, void *buf, size_t n, Qiniu_Off_T off)
{
	Qiniu_Int64 max = self->limit - off;
	if (max <= 0)
	{
		return 0;
	}
	if ((Qiniu_Int64)n > max)
	{
		n = max & (~(size_t)0L);
	}
	memcpy(buf, self->buf + off, n);
	return n;
}

Qiniu_Reader Qiniu_BufReader(Qiniu_ReadBuf *self, const char *buf, size_t bytes)
{
	Qiniu_Reader ret = {self, (Qiniu_FnRead)Qiniu_ReadBuf_Read};
	self->buf = buf;
	self->off = 0;
	self->limit = bytes;
	return ret;
}

Qiniu_ReaderAt Qiniu_BufReaderAt(Qiniu_ReadBuf *self, const char *buf, size_t bytes)
{
	Qiniu_ReaderAt ret = {self, (Qiniu_FnReadAt)Qiniu_ReadBuf_ReadAt};
	self->buf = buf;
	self->off = 0;
	self->limit = bytes;
	return ret;
}

/*============================================================================*/
/* type Qiniu_Section */

static size_t Qiniu_Section_Read(void *buf, size_t unused, size_t n, Qiniu_Section *self)
{
	Qiniu_Int64 max = 0;
	ssize_t readBytes = 0;
	if (self->limit <= self->off)
	{
		return 0;
	}
	max = self->limit - self->off;
	if ((Qiniu_Int64)n > max)
	{
		n = max & (~(size_t)0L);
	}
	readBytes = self->r.ReadAt(self->r.self, buf, n, self->off);
	if (readBytes < 0)
	{
		n = 0;
	}
	else
	{
		n = (size_t)readBytes;
	}
	self->off += n;
	return n;
}

Qiniu_Reader Qiniu_SectionReader(Qiniu_Section *self, Qiniu_ReaderAt r, Qiniu_Off_T off, size_t n)
{
	Qiniu_Reader ret = {self, (Qiniu_FnRead)Qiniu_Section_Read};
	self->r = r;
	self->off = off;
	self->limit = off + n;
	return ret;
}

/*============================================================================*/
/* type Qiniu_Tee */

static size_t Qiniu_Tee_Read(void *buf, size_t unused, size_t n, Qiniu_Tee *self)
{
	size_t nr = self->r.Read(buf, unused, n, self->r.self);
	if (nr > 0)
	{
		return self->w.Write(buf, unused, nr, self->w.self);
	}
	return nr;
}

Qiniu_Reader Qiniu_TeeReader(Qiniu_Tee *self, Qiniu_Reader r, Qiniu_Writer w)
{
	Qiniu_Reader ret = {self, (Qiniu_FnRead)Qiniu_Tee_Read};
	self->r = r;
	self->w = w;
	return ret;
}

/*============================================================================*/
/* type Qiniu_File */

Qiniu_Error Qiniu_File_Open(Qiniu_File **pp, const char *file)
{
	Qiniu_Error err;
	Qiniu_Posix_Handle fd = Qiniu_Posix_Open(file, O_BINARY | O_RDONLY, 0644);
	if (fd != Qiniu_Posix_InvalidHandle)
	{
		err = Qiniu_OK;
		*pp = (Qiniu_File *)(size_t)fd;
	}
	else
	{
		err.code = errno;
		err.message = "open file failed";
	}
	return err;
}

#if defined(_MSC_VER)

#define Qiniu_Posix_Pread Qiniu_Posix_Pread2

int Qiniu_Posix_Fstat(Qiniu_Posix_Handle fd, Qiniu_FileInfo *fi)
{
	int ret = 0;
	Emu_FileInfo fi2;

	Qiniu_Zero(fi2);
	ret = Qiniu_Posix_Fstat2(fd, &fi2);
	if (ret < 0)
	{
		return ret;
	}

	fi->st_size = (Qiniu_Off_T)fi2.st_size;
	fi->st_atime = fi2.st_atime;
	fi->st_mtime = fi2.st_mtime;
	fi->st_ctime = fi2.st_ctime;
	return 0;
}

#endif

Qiniu_Error Qiniu_File_Stat(Qiniu_File *self, Qiniu_FileInfo *fi)
{
	Qiniu_Error err;
	if (Qiniu_Posix_Fstat((Qiniu_Posix_Handle)(size_t)self, fi) != 0)
	{
		err.code = errno;
		err.message = "fstat failed";
	}
	else
	{
#if defined(__APPLE__) && defined(TARGET_OS_MAC)
		fi->st_size >>= 32;
#endif
		err = Qiniu_OK;
	}
	return err;
}

void Qiniu_File_Close(void *self)
{
	Qiniu_Posix_Close((Qiniu_Posix_Handle)(size_t)self);
}

ssize_t Qiniu_File_ReadAt(void *self, void *buf, size_t bytes, Qiniu_Off_T offset)
{
	return Qiniu_Posix_Pread((Qiniu_Posix_Handle)(size_t)self, buf, bytes, offset);
}

Qiniu_ReaderAt Qiniu_FileReaderAt(Qiniu_File *self)
{
	Qiniu_ReaderAt ret = {self, Qiniu_File_ReadAt};
	return ret;
}

/*============================================================================*/
